1. Field of the Invention
This invention relates to aerodynamic reshaping of the external flow environment around a vehicle in supersonic or hypersonic atmospheric flight. More specifically, the invention is a method and system for control of the flowfields upstream of a vehicle in supersonic or hypersonic atmospheric flight.
2. Description of the Related Art
Various high speed vehicles such as aircraft and spacecraft flying through the atmosphere in the supersonic or hypersonic flight regime are subjected to flowfields that have enormous effects on aerodynamic efficiency, the acoustic environment experienced by the vehicle, the aerothermal environment experienced by the vehicle, the complex shock system encountered by the vehicle, and the sonic boom created by the vehicle. The relevance and/or severity of these effects impact vehicle design, the particular flight regime and trajectory being experienced, the payload, etc. Currently, a variety of specialized flow control systems and methods are employed/proposed to individually address the various effects. An example is a mechanical spike for sonic boom mitigation of supersonic aircraft and vehicle design optimization for drag reduction. Accordingly, vehicles that must operate in the supersonic or hypersonic flight regimes are sometimes equipped with systems that are effective for only part of a vehicle's flight, yet must be carried the entire flight. These systems increase the cost, complexity, weight and operational requirements of a vehicle while only providing a limited benefit.
More recently, laboratory studies have investigated the use of cold gas injection into a vehicle's free stream in order to weaken or disperse the shock waves experienced by supersonic or hypersonic vehicles. See “The Dynamics of Shock Dispersion and Interactions in Supersonic Free Streams with Counterflowing Jets,” Endwell O. Daso et al., American Institute of Aeronautics and Astronautics, AIAA-2007-1423, January 2007. Although promising in concept, these laboratory studies do not translate into real-world solutions to improving vehicle performance in supersonic or hypersonic atmospheric flight.